Conventionally, there is known a code symbol reading apparatus that reads a code symbol such as a barcode on an object to be read by scanning the object. In the code symbol reading apparatus as above, a spot of laser beam is irradiated so as to move on the object to be read, and an intensity of reflected light from the object is detected in time-series and analyzed, to thereby obtain information regarding how portions with high reflectance (white bars) and portions with low reflectance (black bars) are arranged.
As such a code symbol reading apparatus, one described in JP 2003-308476 A (PTL1), for example, is known.
The code symbol reading apparatus described in PTL1 pulse-drives a laser diode at a frequency of about 2 MHz, and performs a synchronous detection between a signal of reflected light and an output pulse of an oscillator used for performing the pulse-driving, to thereby cut an input noise.